Characteristics of the Craniofacial Complex in Turner Syndrome

Turner syndrome (TS) is an X chromosome abnormality of females that manifests with varying degrees of dysmorphic features. Objectives: The aim of the present research was to identify characteristics of the craniofacial complex in TS patients from Croatian population. Methods: Cephalometric analysis was carried out on lateral cephalograms of 36 TS patients, aged 10-33 years. There were 19 45,X patients and 17 with other X chromosome aberrations. Fourteen patients, aged 15-33, received estrogen-progestin hormone replacement therapy (HRT), while none received growth hormone therapy. Cephalograms of 72 eugnathic age-matched healthy females served as control. The analysis comprised 35 variables describing cranial base, maxilla, mandible, maxillomandibular and dental relations as described by Midtbo et al. (1996). Results: Logistic regression analysis showed that two variables were significant predictors of TS: posterior cranial base length (s-ba) and mandibular prognathism angle (s-n-sm). On average, s-ba distance was 3mm shorter and s-n-sm angle was 5° smaller than in controls. Sixty-four percent of TS patients and 92% of the controls were classified correctly. Factor analysis revealed clusters of TS patients and controls, formed due to differences in variables s-ba and s-n-sm. Factor rotation showed clusters forming due to differences in variables s-ba, nasion-sella-basion (n-s-ba) and subspinale-basion (ss-ba). On average, n-s-ba angle was 4° larger and ss-ba distance was 4mm shorter than in controls. None of the four variables correlated with age. There was no difference between the two TS kariotype subgroups or between TS patients taking HRT and those not taking HRT. Conclusion: The results indicated that deficient regulatory genes of the X chromosome in TS patients had a direct influence on all three anatomic parts - cranial base, maxilla and mandible – causing irregular growth. This study was supported by the Croatian Ministry of Science, Education and Sports, grants 3-02-383 and 0065004.